Biomedical subjects

Mariko Mochizuki

Publications and source records attributed to Mariko Mochizuki.

8 recordsLinked to original sources

PubMed2006

Invasion assay of Listeria monocytogenes using Vero and Caco-2 cells.

The invasion ability of Listeria monocytogenes into cultured cells has been used to evaluate its pathogenicity. In this study, invasive ability was investigated using Vero and Caco-2 cell lines. The form of invasion showed no morphological differences between both cell lines inoculated with L. monocytogenes L89-H2 or L96-23C1 strains when double fluorescence stained with rhodamine and FITC or with Giemsa staining. Recovery count and recovery rate of L. monocytogenes from Vero cells was related to the number of inoculated bacteria (2 x 10(5) to 2 x 10(7)/ml) in a bell-shape pattern, though the relationship was unclear in Caco-2 cells. Recovery rate of L. monocytogenes was higher in Vero cells than Caco-2 cells at a multiplicity of infection (MOI) 10, though the rates in both cells showed different stable stages over a considerably wide range of MOI. The recovery rate of all five L. monocytogenes strains from listeriosis patients was 15% at MOI 10 from infected Vero cells, while meat-derived strains showed variable rates regardless of the serovar. These results suggest that the Vero cell line is suitable for an invasion assay and that a recovery rate of 15% may be the critical limit for the expression of pathogenicity in the host.

Animals↗

PubMed2005

Discrimination of Listeria monocytogenes contaminated commercial Japanese meats.

Discrimination was attempted on 14 Listeria monocytogenes strains isolated from commercially available Japanese pork and chicken. Examination of the isolates was performed by restriction fragment length polymorphism (RFLP) analysis of the chromosomal DNA and amplified products and comparison of the nucleotide sequences of the amplified products. A polymorphism region containing the repeated sequences in the iap gene was amplified by the polymerase chain reaction (PCR). The genetic analyses could discriminate the 14 isolates in combination with traditional serotyping, and some strains isolated from different meats were confirmed to have a genetically close relationship. Genetic analyses used in the present study would be useful for the elucidation of the pathogen tracks from contaminated sources to humans and of the ecological niche in the food environment.

Animals↗

PubMed2005

Thallium contamination in wild ducks in Japan.

Although thallium (Tl) is toxic to both humans and animals, there is little information on contamination in wildlife. In this study, Tl contents in wild ducks in Japan were determined. Contents of Tl in kidney and liver ranged from 0.42 to 119.61 and 0.10 to 33.94 microg/g dry weight, respectively. Significant correlations between Tl contents in kidney and liver were observed for all dabbling ducks except mallard (Anas platyrhynchos); similar correlations were not observed in diving ducks. Variation in Tl content was observed between sampling locations with the highest mean Tl content in the Eurasian wigeon (Anas penelope) collected in Ibaraki Prefecture.

Animals↗

PubMed2005

Comparison of genomic structures in the serovar 1/2a Listeria monocytogenes isolated from meats and listeriosis patients in Japan.

Foodborne disease by Listeria monocytogenes, serovar 1/2a has recently been reported in many countries. Although contamination by this bacteria is also known to be gradually spreading among the marketed foods of Japan, there is little information on relation between listeriosis and food contamination. In the present study, the characteristics of the genomic structures of serovar 1/2a were compared among the isolates from marketed meats and listeriosis patients. Several isolates from meats purchased at the same shop on different days had the same genomic structure, and prolonged contamination was suggested by the conditions in the shop. Genomic structures of one strain isolated from meat were identical to those of two isolates from a patient. Another isolate was obtained from meats purchased at two different shops, and this isolate was also identical to that of the isolates from another patient. These findings suggest that the isolates from meat may have caused the listeriosis in the patients, and that the strains may have somehow traveled between the shops.

Animals↗

PubMed2004

ARC3, a chloroplast division factor, is a chimera of prokaryotic FtsZ and part of eukaryotic phosphatidylinositol-4-phosphate 5-kinase.

The arc3 (accumulation and replication of chloroplast) mutant of Arabidopsis thaliana has a small number of abnormally large chloroplasts in the cell, suggesting that chloroplast division is arrested in the mutant and ARC3 has an important role in the initiation of chloroplast division. To elucidate the role of ARC3, first we identified the ARC3 gene, and determined the location of ARC3 protein during chloroplast division because the localization and spatial orientation of such division factors are vital for correct chloroplast division. Sequencing analysis showed that ARC3 was a fusion of the prokaryotic FtsZ and part of the eukaryotic phosphatidylinositol-4-phosphate 5-kinase (PIP5K) genes. The PIP5K-homologous region of ARC3 had no catalytic domain but a membrane-occupation-and-recognition-nexus (MORN) repeat motif. Immunofluorescence microscopy, Western blotting analysis and in vitro chloroplast import and protease protection assays revealed that ARC3 protein was soluble, and located on the outer surface of the chloroplast in a ring-like structure at the early stage of chloroplast division. Prokaryotes have one FtsZ as a gene for division but have no ARC3 counterparts, the chimera of FtsZ and PIP5K, suggesting that the ARC3 gene might have been generated from FtsZ as another division factor during the evolution of chloroplast by endosymbiosis.

Amino Acid Motifs↗

PubMed2002

Cadmium contamination in wild birds as an indicator of environmental pollution.

Cadmium (Cd) is an environmental pollutant that has serious toxicity in humans and animals and causes Itai-Itai disease. However, there is little available information on its contamination in wildlife as an indicator of environmental pollution. The Cd contents in the kidney and liver of 85 wild birds from 9 different prefectures in Japan were investigated. The ranges of the Cd contents in the kidney and liver in all birds were ND-174.4 and ND-21.2 microg g(-1) dry wt., respectively. The mean Cd contents were higher in the oil-contaminated birds than those in the non-contaminated ones. Furthermore, a strong correlation was obtained only between the Cd contents in the kidney and those in the liver of the oil-contaminated seabirds and not in the other non-contaminated ones. These results suggest that wild birds reflect the level of environmental contamination which should be monitored.

Animals↗

PubMed2002

The distribution of molybdenum in the tissues of wild ducks.

The Mo contents and the relations between Mo and Cu or Cr contents were investigated in the organs of Japanese wild ducks (spotbill duck, pintail, wigeon, scaup and tufted duck). The highest Mo content in kidney and liver of the dabbling ducks were more than 30 microg g(-1) dry weight (microg g(-1) d. wt.), though that of diving ducks were less than 11 microg g(-1) d. wt. The contents were lower in the ducks migrating within Japan, Eurasia and North America than those in the birds migrating between Japan and Eurasia. The contents of liver in all species were more than 50 and less than 5 microg g(-1) d. wt. for Cu and Cr, respectively. Significant correlations were found between Mo and both elements in pintail and scaup, and Mo and Cr in tufted duck. These results suggest that the contamination of wild ducks reflects the reproductive area, and not the collected area. Mo contents closely correlated with the Cu and/or Cr contaminations.

Animals↗

PubMed2002

Simultaneous analysis for multiple heavy metals in contaminated biological samples.

In the present study, the conditions of analysis by inductively coupled plasma-atomic emission spectrometry (ICP-AES) were investigated. Twenty-six elements (Mg: 25 ppm; Sc: 10 ppm; Ti: 50 ppm; others: 100 ppm) were used as the elements interfering with selected 24 wavelengths. Consequently, the background values in 19 elements were subjected to some influences. However, all of these effects disappeared at low concentrations--less than 1 ppm of interfering elements. Next, the values from the ordinary calibration method were compared with those from the standard addition method using several biological samples. There was a discrepancy in the results obtained from both methods because of the sample, and three patterns were observed. However, no discrepancy was observed in the values for the standard reference materials using both methods. There was no significant difference between the certified values of the standard reference materials and the obtained ones by ICP. Therefore, the analytical wavelengths and the methods in the present study were suggested to be useful for ICP-AES analysis for environmental and/or biological samples.

Calibration↗